Thats not entirely true. Because there is a distinct difference between evolutions. one way we see it, is small changes with in a species to adapt to environment. But the oter view is the gaining of NEW information to transition into a new being. ie reptiles to birds, big differnece between a scale and a feather.
The only difference is that one takes a hundred million years and the other takes thousands.
I mean, there's a difference between running across the hall and running to los angeles, but forrest gump did it, so I can too.
Also, they can demonstrate the creation of "New information". Any "Information" you see is coded into our DNA. Any mutation of Said DNA is new information.
The point is that reptiles and birds: they both use the same Genetic Code, and the differences between the two can really be explained by differences in that. So minor changes to DNA add up.
Here's how it works:
Random mutations, which are processes/copying errors-- These make modifications in the genome.
There are about a hundred or so copying errors per animal per generation...
so if you have a population of 1,000,000 animals born per year over 10,000,000 years, that means you're going to have 1,000,000,000,000,000 ( 1 quadrillion ) chance mutations during that time, at random parts of the genome.
So what natural selection does, is it sorts through these chance mutations, naturally, and picks out the rare ones that actually improve the animal relative to it's environment. Of course there's no guarantee that the fit animal is the one that survives, but that's what usually happens.
So natural selection weeds through these oodles of chance mutations, looking for ones that actually benefit the animal. note, that 99% of mutations do not have any noticable effect, and the other 1% are mostly negative. However, that rare beneficial mutation, when it occurs, tends to flourish. So then, once it appears, the beneficial mutation spreads throughout the population of a species in a few hundred or thousand generations through that great horizontal gene transfer mechanism known as "Sex". So beneficial mutations that arise in one place can spread to all or most members of the species through sex or other methods of horizontal gene transfer in non-sexual species.
So the point is that over the course of time in a population, you have a gazillion mutations which randomly change the DNA, and some of them are bound to be an improvement over what was before. And yes, this is "New Information" by any definition. These changes accumulate over hundreds of millions of years in a population...
( it's also worth noting that most mutations are very minor changes.. it may take several mutations to create a new trait. )
Now, here's when speciation occurs: You take a portion of the population of the above species, and isolate this group from all the other members of the species. Now, by isolated, i mean, doesn't breed, for whatever reason. Maybe it's stranded on an island, crossed a river or something, or they just don't like eachother. So you're not transfering the same genes around through sex ( horizontal transfer ) anymore. The new population is going to produce different random mutations than the old population. Furthremore, it's probably in a different environment, has different worries from predators, is likely to be killed by different things, and eats different things, so what is "Fit" in context of the species is totally different. So you'll have animals that are isolated from their main species, adapting totally separately and going totally different directions. They have different random mutations, and different selective pressures. If you isolate them for long enough, they won't interbreed with the main species ever again, eventually they'll be incapable... after which point they just get farther and farther apart, as evolution takes them in different directions... So that's how you get a new species.
and eventually you have things which share a common ancestor, yet look nothing alike.
I mean, it takes hundreds of million years for a reptile to turn into a bird. But, this change isn't inherantly different than the microevolution that creationists will believe... the point is that microevolution accumulates and becomes macroevolution. The difference between birds and modern reptiles can be understood by comparing the differences between the two, the differences are just a bunch of chance mutations that arose over time and were selected for differently in different populations.